<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <span class="iconfont header-back-abs">&#xe743;</span>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      <router-link to="/">
        <span class="iconfont header-fixed-back">&#xe743;</span>
      </router-link>景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: "DetailHeader",
  data() {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    };
  },
  methods: {
    handleScroll() {
      let scrollTop =
          document.documentElement.scrollTop ||
          document.body.scrollTop ||
          document.querySelector('.div').scrollTop;
        if (scrollTop > 60) {
          let opacity = scrollTop / 140;
          opacity = opacity > 1 ? 1 : opacity;
          this.opacityStyle = { opacity };
          this.showAbs = false;
        } else {
          this.showAbs = true;
        }
        console.log('scroll');
        
    }
  },
  created() {
    window.addEventListener(
      "scroll",
      this.handleScroll,
      true
    );
  },
  destroyed() {
    window.removeEventListener(
      "scroll",
      this.handleScroll,
      true
    );
  }
};
</script>

<style lang="stylus" scoped>
@import '~@/assets/style/variable.styl';

.header-abs {
  position: absolute;
  left: 0.2rem;
  top: 0.2rem;
  width: 0.8rem;
  height: 0.8rem;
  line-height: 0.8rem;
  text-align: center;
  border-radius: 0.4rem;
  background: rgba(0, 0, 0, 0.8);
}

.header-abs-back {
  color: #fff;
  font-size: 0.4rem;
}

.header-fixed {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 1.2rem;
  line-height: 1.2rem;
  text-align: center;
  color: #fff;
  background: $bgColor;
  font-size: 0.32rem;
  z-index: 9;
}

.header-fixed-back {
  position: absolute;
  width: 0.64rem;
  text-align: center;
  font-size: 0.4rem;
  top: 0;
  left: 0;
  color: #fff;
}
</style>